This invention relates to a logistic method in a tunnel-composting plant for the transportation and handling of the materials, in which method
the materials brought to the plant for composting, dried municipal sludges, separately collected organic wastes, industrial organic wastes and/or dried sludges, as well as the supporting and/or mixing materials required by the composting process, such as woodchips, bark and/or peat, are unloaded at intermediate collection points, and PA1 a compostable material is mixed, sieved, and crushed, according to the current recipe, from the materials collected, and PA1 the materials to be composted are transferred to form a batch for composting in the composting tunnel that is currently free, and PA1 each batch is composted in the composting tunnel with the aid of powerful air circulation directed through the material, PA1 after composting, the composted batch of finished material is transferred from the composting tunnel to a heap of finished material at its own collection point, PA1 the composted material is transported from the heap of finished material to the desired point of use for possible further maturing.
In a tunnel composting plant there are usually several parallel composting tunnels or reactors, into which the material to be composted, together with the support and mixing materials, is transferred. The base has air-holes, through which a strong flow of air is blown through the material, the air being generally recirculated through a gas washer back to the composting tunnel. The finished material is transferred to a further composting stockpile, where it is allowed to finally mature. After this, the material is taken to be used directly either as fertilizer, or as soil improvement material, or else it receives further treatment for other purposes.
The materials brought to the plant vary widely in their treatability. Often organic waste demands considerable pre-treatment, particularly crushing, before it can be fed to the process. It is also often necessary to sieve several components. On the other hand, support and mixing materials, such as woodchips, bark, and peat are generally quite easy to handle. In known composting plants handling municipal or industrial organic waste, there is a considerable amount of various mixing, crushing, and other pretreatment equipment, which prepares the material to be transferred to the composting tunnel. The movement of material in these plants takes place mainly by means of special conveyor devices, which move the mixed material, for example, from an intermediate storage silo to a composting tunnel. The composting tunnel itself generally also includes its own mixing and transfer devices. In these plants, the material is also often removed from the composting tunnel by means of special transfer devices.
Tunnel composting plants, in which conveyor equipment is used to transfer the material to the composting tunnel and from it, are known from German patent publications DE 2937390, DE 2948176 (=FI67685) and DE 2809344.
In small plants that mainly compost garden waste, the material need not be mixed, sieved, or crushed. In some plants of this kind, the garden waste is transferred as such to and from the composting tunnel by means of an ordinary wheeled loader. Plants of this kind are not suitable for materials that are more difficult to handle, such as, for example, organic waste and dried sludge.
There are certain basic costs attached to the handling of the material and conveyor equipment, due to which these form a very large part of costs, especially in small plants. As the size of the plant increases, the costs of the mixing, sieving, crushing, and conveyor equipment grow quite slowly when compared, for example, to construction costs.
In small plants, the emptying and filling of the composting tunnel take place, for instance, once a week. This means that the sieving, crushing, mixing, and conveyor equipment stands idle for most of the time.
If good quality material is wanted, the composted material must be crushed and mixed one more time, before being put on the heap for further maturing.
This invention is intended to create a new kind of logistic method for handling and transporting the aforementioned difficult materials in the process in a tunnel composting plant. According to the method, the materials brought to the plant for composting, dried municipal sludges, separately collected organic wastes, industrial organic wastes and/or dried sludges, as well as the supporting and/or mixing materials required by the composting process, such as woodchips, bark and/or peat, are unloaded at intermediate collection points. A compostable material is mixed, sieved, and crushed, according to the current recipe, from the materials collected, and the materials to be composted are transferred to form a batch for composting in the composting tunnel that is currently free.
Each batch is composted in the composting tunnel with the aid of powerful air circulation directed through the material. After composting, the composted batch of finished material is transferred from the composting tunnel to its own collection point. The composted material is transported from its aforementioned collection point to the desired point of use for possible further maturing.
The intermediate collection points of the materials to be handled and the collection point of the finished material are established on a loading base capable of supporting a vehicle, each as a heap with free access for the bucket of the implement from at least one side. Each composting tunnel has a floor capable of supporting a vehicle and a door equipped with an access opening permitting the transfer of the material by a wheeled vehicle. Essentially all the handling of the materials at the plant, i.e. mixing, sieving, crushing, and transfer between the intermediate collection points, the composting tunnels, and the collection point for the finished material, is carried out using a wheeled loader equipped with a mixing and crushing bucket, so that a single wheeled loader of this type can carry out essentially all of the aforementioned work stages. Accordingly the compostable material is mixed by the aforesaid bucket so effectively, that intermediate mixing is not necessary in the composting tunnel during composting.
A tunnel composting plant according to the invention, includes at least one tunnel composting tunnel, devices for circulating air through the material stored in the composting tunnel, intermediate collection points, for the materials brought to the plant for treatment, a collection point for finished, outgoing material, implements for mixing, sieving, and crushing the materials being handled, implements for transporting the material to the composting tunnel, and implements for transporting composted materials from the composting materials to its own collection point. Therein the tunnel-composted materials are dried municipal sludges, separately collected organic wastes, industrial organic wastes and/or sludges, and on the other hand support and mixing materials such as, for example, peat, woodchips, and bark.
The intermediate collection points for the materials to be handled and the collection point for the finished material are, in their structure, loading bases capable of supporting a vehicle and each is a heap with free access from at least one side for the bucket of an implement. Each composting tunnel has a floor capable of supporting a vehicle and a door equipped with an opening permitting the transfer of material by means of a wheeled vehicle. The aforementioned implements for handling and transporting the materials, i.e. the implements for mixing, sieving, crushing, and transporting the materials consist of at least one wheeled loader, equipped with a mixing and crushing bucket.
Nowadays, wheeled loaders, equipped with a mixing bucket, that are as such known, can carry out many work stages that previously required several different machines. In addition, the same machine can be used to carry out treatments taking place in different places, for example, crushing at the beginning and end of the process--an arrangement that would have been impossible earlier in a plant equipped with fixed conveyor devices. Thus a single wheeled loader can replace a large amount of fixed handling equipment, such as a crusher, sieve, and mixer, and conveyors. Particularly if the plant uses an outside contractor, the plant need not invest in handling and transfer equipment that stands idle for long periods, and the place of which is here taken by a single wheeled loader.
Other advantages and characteristics of the invention will become obvious from the examples of embodiments described later.
In what follows, the invention is described with reference to the accompanying Figures, which show one tunnel composting plant according to the invention, particularly its logistics.